Exodus 21:2 - Coke's Commentary on the Holy Bible

If thou buy an Hebrew servant, &c.— The laws respecting male and female Hebrew servants, or slaves, are here delivered first; no doubt, to impress the just feelings of humanity towards them. Tertullian elegantly calls these laws the precepts of humanity; a just denomination, if we consider the dispensation under which they were decreed. Perpetual slavery is absolutely forbidden. Six years was the utmost term of slavery: to which they were sold, sometimes as malefactors by the judges, ch. Exodus 22:3 sometimes as insolvent debtors to their creditors, 2 Kings 4:1. Matthew 18:25 and sometimes, through extreme poverty, persons sold themselves, Leviticus 25:39.; in which last case parents also might sell their children. No such slave was to serve longer than six years; on the seventh, or on the year of jubilee, (of which more will be said hereafter,) he was to go out free.